Asst 1

course PHY 121

MYCšʈ~assignment #001

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001.

Physics I

02-11-2008

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21:09:51

`questionNumber 10000

Explain in your own words how the standard deviation of a set of numbers is calculuated.

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RESPONSE -->

To get the standard deviation you square the deviations and average them and then take the square root.

confidence assessment: 3

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21:12:12

`questionNumber 10000

Explain in your own words the process of fitting a straight line to a graph of y vs. x data, and briefly discuss the nature of the uncertainties encountered in the process. For example, you might address the question of how two different people, given the same graph, might obtain different results for the slope and the vertical intercept.

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RESPONSE -->

The process of fitting a straight line can be hard to do. People can look at the same graph and without very accurately labeled graphs 2 different people may estimate different x,y values in coordinates.

confidence assessment: 2

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21:14:21

`questionNumber 10000

Briefly state what you think velocity is and how you think it is an example of a rate.

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RESPONSE -->

velocity is a rate because it is calculated as a change in position/change in time.

confidence assessment: 1

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21:14:31

`questionNumber 10000

** A rate is a change in something divided by a change in something else.

This question concerns velocity, which is the rate of change of position: change in position divided by change in clock time. **

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RESPONSE -->

good.

self critique assessment: 3

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21:15:08

`questionNumber 10000

Given average speed and time interval how do you find distance moved?

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RESPONSE -->

d = average speed * time

confidence assessment: 3

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21:15:19

`questionNumber 10000

** You multiply average speed * time interval to find distance moved.

For example, 50 miles / hour * 3 hours = 150 miles. **

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RESPONSE -->

good.

self critique assessment: 3

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21:18:08

`questionNumber 10000

Given average speed and distance moved how do you find the corresponding time interval?

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RESPONSE -->

time = average speed * distance

confidence assessment: 1

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21:18:56

`questionNumber 10000

** time interval = distance / average speed. For example if we travel 100 miles at 50 mph it takes 2 hours--we divide the distance by the speed.

In symbols, if `ds = vAve * `dt then `dt = `ds/vAve.

Also note that (cm/s ) / s = cm/s^2, not sec, whereas cm / (cm/s) = cm * s / cm = s, as appropriate in a calculation of `dt. **

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RESPONSE -->

and of course i did the opposite. got it now.

self critique assessment: 1

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21:19:35

`questionNumber 10000

Given time interval and distance moved how do you get average speed?

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RESPONSE -->

average speed = distance/time

confidence assessment: 2

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21:19:50

`questionNumber 10000

** Average speed = distance / change in clock time. This is the definition of average speed.

For example if we travel 300 miles in 5 hours we have been traveling at an average speed of 300 miles / 5 hours = 60 miles / hour. **

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RESPONSE -->

:)

self critique assessment: 3

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Your work looks good. Let me know if you have any questions. &#